15'' wheels

Is anyone running 15'' wheels on a 90's Suburban? I was under the impression that minimum wheel diameter for my 99 would be 16''. Trying to clear this up before i get new wheels. Wanna get my some 15x8 black steelies.

My 2wd 1500 1998 Suburban came with 235/75 15 tires wheels-
I suspect those tiny tires help the mpg-
They do look "small" but work just fine
And it is very easy on tires-
Bought it 23000 miles ago-had 20% left on front 50% on rear-still using those tires 23000 miles later(fronts are worn out- but I'll get another 6 months out of them)-decent tires might last 100,000 miles on this vehicle

I have black steel wheels on mine, but they aren't 15". I think I put on 17" wheels? I'll have to walk outside and look. I bought four spares from the 2000+ trucks, because their spare wheels are black steel. I think they look good!